1. Technical Field
The present invention relates to a polarization conversion element, a light source device, a lighting device, and a projector.
2. Related Art
In the related art, a projector which modulates illumination light emitted from a light source device to form an image in accordance with image information and enlarges and projects the image on a projection surface such as a screen or the like has been known (for example, see JP-A-2011-197212).
The projector disclosed in JP-A-2011-197212 includes a lighting device, a color separation device, a light modulation device, a light combining device, and a projection optical device. Among these, the lighting device includes a solid-state light source device, a condensing optical system, a rotation fluorescent plate, a motor, a collimate optical system, a first lens array, a second lens array, a polarization conversion element, and a superimposing lens. In this lighting device, light emitted from the solid-state light source device is concentrated by the condensing optical system and is incident to the rotation fluorescent plate rotated due to the motor. The light incident to the rotation fluorescent plate is emitted from the rotation fluorescent plate as fluorescent light and becomes light collimated by the collimate optical system, and the light is incident to the polarization conversion element via the first lens array and the second lens array. This polarization conversion element has a configuration in which a plurality of polarization separation layers and a plurality of reflecting layers are alternately arranged along one direction in a plane orthogonal to an optical axis, and light having polarization directions aligned by the polarization conversion element is superimposed by the superimposing lens and emitted from the lighting device as illumination light.
However, the polarization conversion element of the projector disclosed in JP-A-2011-197212 has a configuration in which polarization separation layers and reflecting layers are alternately arranged along one direction in a plane orthogonal to an optical axis as described above, and thus, the configuration is complicated.